2004 Lexus GX 470 inside pistons will not push all the way

BRAKOCREP2

MEMBER
2004 LEXUS GX 470
V8
4WD
AUTOMATIC
80,000 MILES

I have this car and am doing a brake job. The rears were no problem, however the fronts seem to have calipers seem to have dual pistons on both sides. Never had a car with this before. The pistons on the outside of the rotor on both sides push back into the caliper all the way for me to slide the new pad in. However the inside pistons will not completely return on the passenger side and the pistons on the driver side the top one returns all the way however the bottom does not. Wondering if the calipers need replacing. I have replaced the rotors. Hope you write soon need car asap.
Thanks Brandon

3 Replies

CARADIODOC

MECHANIC
33,916 POSTS

Hi Brandon. Bolt the calipers back in place without the pads, then use a large flat blade screwdriver to slowly pry the pistons back in. If they don't go in freely, loosen the cap on the fluid reservoir. If that doesn't help, open a bleeder screw and try again. If they still don't go in, there could be crud buildup behind the pistons but that shouldn't really be a big problem with a six-year-old car.

Caradioodc

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Thursday, November 11th, 2010 AT 12:19 AM

BRAKOCREP2

MEMBER
2 POSTS

I have already tried everything you suggested yesterday, would you now suggest I replace calipers.
Brandon

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Thursday, November 11th, 2010 AT 7:43 AM

CARADIODOC

MECHANIC
33,916 POSTS

I can't argue with your results but it's surprising to think there is crud built up behind the pistons on such a relatively new car. Is it possible the pistons move so freely that one is coming out when you press the other one in? I'm sure new calipers will solve the problem of not being able to fit the new pads in unless you have the wrong pads. Normally the wrong pads are significantly different so it's easy to see when you compare them but you might want to double check the parts you were sold.

Caradiodoc

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Thursday, November 11th, 2010 AT 8:22 AM